Red vat-dye.



UNITED STATES PATENT oFFroE.

KARL SCHIRMACHER AND ARNOLD BRUNNER, OF HOCHST-ON-THE-MAIN, GERMANY,

.ASSIGNORS TO FARBWERKE VORM. MEISTER LUCIUS & BRUNING, OF HOCHST-ON- THE-MAIN, GERMANY, A CORPORATION OF GERMANY. f

RED- VAT-DYE.

. Specification of Letters Patent.

PatentedMarch 10, 1908.

Application filed February 20, 1907. Serial No. 358,421.

To all whom it may concern:

fie it known that we, KARL SCHIRMACHER, PIIID and ARNOLD BRUNNER, Ph. D., chemists, citizens of the Empire of Germany, and yesiding at Htichst-on-the-Main, Germany, have 'fiiventedcertain new and useful 1m: provements in Making New Red Vat-Dyestufis, of which the following is a specification.

We have found anew red vat dyestuff distinguished by its beauty and fastness of its tints.

The dyestufl is a red powder insoluble in water, difficultly soluble in hot alcohol, more easily Soluble in hot glacial acetic acid, ben-- zene and chloroform with a yellow-red color, soluble in concentrated sulfuric acid with a green color.

With alkaline hydrosulfite it yields a yellowish solution from which wool and cotton are dyed fast tints similar to alizarin pink.

This dyestuif may 'be'obtaine-d, for instance, as follows Examplell: 16.5 parts by weight of orthonitro-metaexylidin are diazotized with 6.9 parts by weight of nitrite and 40 parts by weight of hydrochloric acid of 20 B. specific gravity and the filtered diazo solution is introduced at gentle heat into a solution of copper-cyanid resulting from 25 parts by weight of copper. sulfate and 28 parts by wei ht of potassium cyanid.

The nitrite is separated while nitrogen is by Weight of sulfuric acidof 90% strength, till a complete solution is efiected. There The constitution of same corresponds in cold water.

When cold water and aconcentrated solution of 13 parts by weight of nitrite is gradually introduced in the heat, while stirring, below the surface of the liquid. When all is run in, heating is continued for another hour; the solution is then allowed to cool and the separated nitroxylic acid (OH :OH :NO :COOH= 6242221) is filtered. In a pure state the acid is nearly colorless, readily soluble in alcohol from which it is precipitated on addition of water. It dissolves in hot water from which it crystallizes when cold in small yellowish crystals. It melts at about 189 C.

To reduce the nitro-xylic acid 20 parts by weight of this compound are dissolved in 5.6 parts by weight of sodium carbonate to which are added 11 parts by weight of sodium di-sulfid and the whole is boiled for some hours. It is then acidified with acetic acid and much evaporated. The residue is treated with concentrated hydrochloric acid in the cold until acid reaction and then filtered. The solution contains the o-amino- Xylicacid (CH CH NH zCOOH= 614E521).-

The diazo compound obtained from this acid are then added about 350 parts by weight of Y by adding 25 parts by weight of hydrochloric acid and 6.9 parts by weight nitrite is introduced into a solution of 18 parts by weight of potassium xanthogenate and 40 parts by weight of sodium carbonate. After stirring several hours, 15 parts by weight of sodium chloracetate and 25 parts by weight of caustic soda-lye 40 B. are added and the whole is heated to 100 C. for several hours. lVhen cold it is acidified with mineral acids, whereupon the 2.4-Xylylthioglycollic-orthocarboxylic acid 011,:011, .sorncoon .coon 6 .412 1 is precipitated. It is soluble with difficulty To manufacture the dimethyl-oxythionaphthene carboxylic acid 20 parts by weight of the xylylthioglycollic-ortho-carboxylic acid are heated to 180190 O. for some time with a mixture of 120 parts by weight of caustic soda and 12 parts by weight of water. The mass assumes gradually a yellowish tint. When cold it is dissolved in water and thena solution of potassium ferri cyanid is added until-nomore of the dyestufi separating in red flakes is formed.

The dyestufi is filtered and washed with water. When dry it is a red powder, soluble in alkaline hydrosulfite with formation of a yellow colored vat. From this vat Wool and cotton are dyed similar to the shade of alizarin-pink. This dyestufl' compared with thioindigo is particularly distinguished by its excellent fastness to Washing.

Having now described our invention, What We claim is I 10 As product the red vat dyestufl which corresponds to the constitutional formula 15 being a red powder insoluble in water, very diflicultly soluble in hot alcohol, more easily soluble in hot benzene, glacial acetic acid and chloroform with a red color; soluble in concentrated sulfuric acid with a green color, forming with alkaline hydrosulfite a yellow 20 vat from which wool and cotton are dyed fast tints to alizarin-pink.

In testimony, that we claim the foregoing as our invention, we have signed our names in presence of two subscribing witnesses.

KARL SCHIRMACHER. ARNOLD BRUNNER; W'itnesses JEAN GRLXD, CARL GRL'XD. 

